From simulations of white dwarf mergers, [1]} found that T\(_{\rm {He}}\)  is inversely correlated with the mass ratio (\(q =\)  M\(_{\rm {He}}\) /M\(_{\rm {CO}}\) ). They derive values of T\(_{\rm {He}} = 3\) , 2.5 and \(1.5 \times 10^{8}\)  K for \(q=0.5\) , 0.6 and 0.7 respectively. The helium shell temperatures of dLHdC stars are consistent with mass ratios \(0.5<q<0.6\) . RCB stars are consistent either with \(q>0.6\)  or \(q<0.5\)  depending on whether they have T\(_{\rm {He}} < 2.5\times 10^{8}\)  K or T\(_{\rm {He}}>3.5\times 10^{8}\)  K, respectively. However the [1]} analysis does not include an important factor – additional energy contributions from nucleosynthesis in the shell. This additional energy will increase the shell temperature, and thus the above estimates of T\(_{\rm {He}}\)  are likely lower limits, and the \(q\)  ranges are unrealistic. No studies of temperature increase due to nucleosynthesis exist in literature.
